SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f7bbe1d6fccfeca71810d11ed268b48d437a7ee676732a84814b0c52df76cd2' 
  AND token = 'LOvIRij9pdLusNbT+RyrQKVLsS7LJUk40aQOKE6daO4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}